Крейн Д., Паскарелло Э., Джеймс Д,. AJAX в действии / Ajax в действии / Исходники примеров / ajaxinactioncode_03nov2005 / ch11 / server_src / src / com / manning / ajaxinaction / web / GenericSecurityFilter

package com.manning.ajaxinaction.web;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
* filter for restricting source of requests for ajax data feeds
*
* @author dave
*/
public abstract class GenericSecurityFilter implements Filter {

protected String rejectUrl=null;
/* (non-Javadoc)
* @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
*/
public void init(FilterConfig config) throws ServletException {
rejectUrl=config.getInitParameter("rejectUrl");
}

/* (non-Javadoc)
* @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {

if (isValidRequest(request)){
chain.doFilter(request, response);
}else if (rejectUrl!=null){
RequestDispatcher dispatcher = request.getRequestDispatcher(rejectUrl);
dispatcher.forward(request, response);
}
}

protected abstract boolean isValidRequest(ServletRequest request);

/* (non-Javadoc)
* @see javax.servlet.Filter#destroy()
*/
public void destroy() {
}

}